Sounds like he has issues to me.
So if I write and record a song and then perform it publically I have "assaulted" everyone's ears with my song and they can now take it and do what they want with it including recording it and selling it.
Yeah, the guy is nuts.
Great artistic ability however.
I can't speak for Banksy, but that sounds like a different thing to what he was describing. If you wrote a song, then produced an album cover art with your ass hanging out
and pasted it on all the bus stops in the county, then that would be more like the intrusion he's talking about. You've lost your ownership of it by pasting it everywhere for everyone to see whether they wanted to or not.
Obviously it's not the legal standpoint, hence his tendency toward anonymity. I can sort of appreciate what he's saying.